In numerous diseases, as, for example, in diabetic neuropathy, the examination of temperature perception and pain sensation is used for early diagnosis as well as for controlling the courses of disease and therapy. The warm-cold-perception as well as the faculty of perceiving pain caused by heat are examined, both of which reflect the functional status of the little nerve endings. The stimulator is brought into contact with a suitable part of the patient's body. Starting from a mean temperature the temperatures of the stimulator are raised or lowered. The patient states at what time he notices a change in temperature (warm-cold-perception) or when he first feels pain (pain sensation). In a patient with, for example, diabetic neuropathy the warm-cold-perception as well as the pain sensation is shifted to higher values. The same applies to other diseases with an impairment of the thin nerve endings, so that in these cases a diagnosis and therapy valuation can be performed with the above mentioned method.
A stimulation device of the kind described at the beginning is known from a prospectus of the firm Medelec Ltd., entitled "TTT". The stimulator is arranged in and firmly connected to the casing. The Peltier element is heated up or cooled down in correspondence with the direction of the current supplied to the Peltier element. The stimulator is connected to the Peltier element in such a way that the heat is transmitted to the stimulator correspondingly. The stimulation device is brought into contact with a suitable part of the patient's body, for example, with the hand or with the foot. In the following examinations it turned out to be a disadvantage that the test results depend on the bearing pressure of the stimulator. The bearing pressure cannot be adjusted exactly in the devices known up to now. This increases the measuring error, thus reducing the reliability of measurements. The DE-OS 33 09 093 describes a device for measuring the function of blood circulation of the skin, where a certain part of the skin is heated up and the course of temperature is measured on a spot that was not heated up in the midst of the heated-up area. The device comprises a casing, in which a fluid-operated piston supported by a recuperating spring is arranged movably, which carries a component of the Peltier element, thus making the contact of the Peltier element with the patient's skin possible. The reaction force of the pneumatic pressure acting upon the casing requires that the weight of the casing is great enough for this reaction force to develop and that the casing is not lifted from the patient's skin. This construction further requires that the casing can only be put on the patient's skin from the top pointing vertically downwards. A reverse positioning, or even the positioning on a vertical part of the patient, as, for example, on the cheek or on part of the foot, is not possible. In any case, however, the patient is exposed to the considerable weight of the casing, so that, there is the risk that the area to be examined is excessively compressed by this weight leading to a reduced blood circulation of the resp. area and thus, of course, to a distortion of the measuring result.
The DE-OS 29 12 349 describes a device for the determination of the moisture state of the human skin, in which an electrode holder is mounted to a spring and has a projection in relation to a casing and which can be attached to and pressed against the patient's skin against the resistance of the spring, until the projection has disappeared. Obviously, the pressing against the human skin is carried out manually and is therefore variable and not reproducible with regard to the pressure.